Op-art architecture designed for happiness.

The beautiful baroque library of the Hapsburg empire.

An exquisite Baroque church in Vienna's old town.

Legends surround an ancient tree trunk riddled with nails for good luck.

Built to give thanks for the passing of a plague epidemic, this cathedral is a one-of-a-kind architectural hybrid.

A spherical "micro-nation" in the heart of Vienna.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

A small museum filled with over 1,000 clocks, and one particular clock calibrated to run until the year 9999.

Vienna's underworld of tunnels and subterranean rivers made an iconic appearance in a 1949 Orson Welles film.

Baroque celebration of the end of the Great Plague of Vienna.

Slaughterhouse Five opens its dank doors to fans of Kurt Vonnegut.

The largest treasure hoard in Europe is contained in a castle that was bombed out during World War II.

An exquisite panometer representing Dresden as it was from 1695 to 1760.

To the great disappointment of doomsdayers, this codex merely contains records of the Moon and Venus.

A unique hanging cable-car navigates through Dresden, the oldest suspension railway in the world.

In addition to fine dairy products, the world's most beautiful milk shop also offers a feast for the eyes.

When the rain falls, this drain system turns into a musical instrument.

One of the world's heaviest musical instruments towers within a popular urban park.

These brass bunnies honor the rabbits that dominated the no-man's-land around the Berlin Wall.

A traditional U-Bahn station in Berlin gets a string of rather untraditional benches.

The world's first clock to use set theory as a measure of time required the invention of a new light bulb just to maintain its obtuse measurements.

The walls of Germany's Parliament still show the scars of the Red Army takeover in World War II.

Berlin's oldest surviving academic architecture hosted decades of animal dissections.